3. Amphoteric hydroxides a) Take 5-6 drops of a solution of any chromium (III) salt and add dropwise a diluted solution of sodium hydroxide until the precipitate of chromium hydroxide is formed. Divide the precipitate of Cr(OH)_(3) into two parts and dissolve them in NaOH and HCl respectively. Observation __

To complete the observation for the given experiment, we need to understand the behavior of chromium(III) hydroxide (\(Cr(OH)_3\)) in different solutions.<br /><br />When \(Cr(OH)_3\) is dissolved in sodium hydroxide (NaOH), a strong base, the hydroxide ions (OH-) from NaOH will not significantly change the equilibrium of \(Cr(OH)_3\). Therefore, the solution will remain blue, indicating that the chromium(III) ions are in their hydroxide form and not significantly altered by the presence of excess hydroxide ions.<br /><br />On the other hand, when \(Cr(OH)_3\) is dissolved in hydrochloric acid (HCl), a strong acid, the hydrogen ions (H+) from HCl will react with the hydroxide ions from \(Cr(OH)_3\), forming water and leaving the chromium(III) ions in a different oxidation state. This change in oxidation state will result in a green solution.<br /><br />Therefore, the observation for the experiment would be:<br /><br />- When \(Cr(OH)_3\) is dissolved in NaOH, the solution remains blue.<br />- When \(Cr(OH)_3\) is dissolved in HCl, the solution turns green.<br /><br />This confirms that \(Cr(OH)_3\) is amphoteric, as it can dissolve in both basic and acidic solutions, resulting in different colors.